Scientists say more major flooding a matter of time

Iowa is seeing heavier rainstorms every year and scientists say it’s only a matter of time before the state is hit by yet another major flood. Richard Cruse, an agronomist at Iowa State University, says many communities are still recovering from previous flood disasters, like the ones that hit Cedar Rapids in 2008 and central Iowa in 2010.

“What we’re seeing in Iowa is this increased frequency of these very intense rainstorms,” Cruse says. “In the period of 1970 to 2005, the frequency of these very heavy events has increased 30%. When you couple the intensive row crop production with these very heavy rainstorms, it is a really ugly picture.”

Cruse says the homogenization of Iowa’s landscape is a major contributor to the state’s flood risk. He points to the dominance of corn and soybeans, which has vastly reduced Iowa’s absorbent prairie grass, wetlands, and forests. Cruse says restoring even some of that diversity would significantly reduce flood risk.

“We know that you could take 10% of the land that’s currently in row crop, and reduce soil erosion losses by way more than 50%,” Cruse says. “It doesn’t make a lot of sense to farm areas that are flooding every other, every third, even every fourth year. Those areas could be put into perennials and probably not lose any total economic return.”

Some Iowa landowners are restoring wetlands and working to prevent flooding on their properties. Laura Krouse, ripped out four acres of corn on her Mount Vernon farm and built a wetland area. It sits on only four-percent of her farmland, but absorbs nearly all the water that used to run right off it.

“We forced basically all the surface water and all the water that comes out of the tiles goes down here and goes to the surface,” Krouse says. “So, even if we get a really big rain event, some of it is going to get stored before it starts to release to the stream below.” Still, the demand for corn and soybeans is intensifying. Prices continue to rise for both.

Traders say Iowa will need to grow 500,000 more acres of corn than it did last year if the nation’s going to prevent price spikes, maybe even rationing. As drought in other parts of the world drives up demand for Iowa’s crops, the state faces a conundrum: the more homogenized the land becomes to meet that need, the greater our own risk of flooding here at home.